Eduqas Chemistry for A Level Year 2: Student Bk

Practical work ??? You should be able to demonstrate and apply knowledge and understanding of: How stereoisomerism is distinct from structural isomerism and that stereoisomerism encompasses E-Z isomerism and optical isomerism. The terms chiral centre, enantiomer, optical activity and racemic mixture. Optical isomerism in terms of an asymmetric carbon atom. The effect of an enantiomer on plane polarised light. 114 Content 115 The distinction between structural isomerism and optical isomerism and the two types of stereoisomerism 116 Common terms used in optical isomerism 116 Recognising the features present in organic formulae that lead to optical isomerism 117 The effect of enantiomers on plane polarised light Molecules of organic compounds often contain a large number of atoms. For example, a molecule of the explosive TNT, C 6 H 2 (CH 3 )(NO 2 ) 3 , has 21 atoms from four different elements, and a molecule of sucrose, C 12 H 22 O 11 , has 45 atoms. Even in the simpler molecule having a molecular formula C 2 H 6 O, the atoms can be arranged to give ethanol, C 2 H 5 OH or bonded together with a central oxygen atom to give methoxymethane, CH 3 OCH 3 . Compounds that have the same molecular formula but are bonded differently are called structural isomers. There is another type of isomerism where differences arise because of the position the atoms take up in space. We call this stereoisomerism. In the first year of this course, we have met E-Z isomerism and we now look at another form of stereoisomerism, optical isomerism. OA1.1 Stereoisomerism Component 2